Stop firefox from playing media player files automatically

Firefox has an inbuilt feature that lets firefox running on windows to play embedded windows media player files automatically on a web page. This feature has both good and bad part. The good part is that you are able to view media player files inside your web browser, without the need of downloading and playing them separately, whereas the bad part is that sometimes you view unnecessary video that consume your bandwidth and time. To disable firefox from playing media player files automatically you need to make the following changes:-